When a mobile terminal (such as a mobile phone) uses only an application lock set by a lock screen application to lock the screen, the lock screen application records the number of failed attempts to unlock the application lock. When an attempt to unlock the application lock fails, the lock screen application will determine whether the number of the failed attempts to unlock the application lock reaches a threshold. If the number of the failed attempts has reached the threshold, the lock screen application will start the camera of the mobile terminal to take a picture, output the warning information to prompt that the mobile phone may be lost.
However, in the prior art, in the case that both the system lock and the application lock set by the lock screen application are set in the mobile terminal, if unlocking the system lock fails, the lock screen application cannot output the warning information, regardless of whether the system lock is a fingerprint lock or a password lock, and thus the user cannot timely learn that the mobile terminal is lost.